The objective of this project is to characterize the genetic mechanisms of antibody expression, regulation and diversification. The approach is the identification and detailed linkage of antibody variable and constant region structural genes to determine their number, organization and location in the genome. The location and linkage relationships will help to reveal the mechanisms of gene expression. The number of variable region genes will show the relative contributions to overally antibody diversity of germ line gene content compared with ensuing somatic diversification. We will identify new antibody genes through the study of NZB myeloma proteins and by screening DNAs from various strains of mice by Southern blot analysis. We will identify new antibody genes through the study of NZB myeloma proteins and by screening DNAs from various strains of mice by Southern blot analysis. We will study allelic exclusion on non-antibody genes linked to allotype. We will determine the genetic factors responsible for autoimmunity in NZB mice by analyzing the NZB x C58 Recombinant Inbred strains.